import java.util.Scanner;
public class Task02 {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		float sum = 0;
		float x;
		
		do {
			x = sc.nextFloat();
			sum += x;
			
		} while (x != 0);
		
		System.out.println(sum);
		sc.close();

	}

}
